The first expansion, RBO Extra Scenario Vol. 1, was released on August 14, 2005. Scenario Vol. 1 added two new stages, an arena mode with 50 stages (10 of them are unlocked by finishing the previous 40 with each class), some character balances, and increased difficulty such as doubling boss and mini-boss damage.

A second expansion, RBO Extra Scenario Vol. 2, was released on December 29, 2005. Scenario Vol. 2 added three new levels, decreased the requirements for unlocking the extra arenas from all classes to two classes, and further tweaked gameplay.

The third expansion, RBO Extra Scenario Vol. 3, was released on May 21, 2006. Scenario Vol. 3 added one new level.